4x - 5y = 5 ①2x + 3y = -25 ②方法1：这是推荐方法① - 2 X ② > y = 4x / 5 - 1 ③③代入到② 得到 2x + 3(4x / 5 - 1) = -25整理得到,22x/5 = - 22 ,所以 x = - 5 代入到③得到 y = - 4 - 1 = - 5...